Note: Descriptions are shown in the official language in which they were submitted.
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ERGONOMIC HAND WHEEL FOR RAILWAY CAR HAND BRAKE
FIELD OF THE INVENTION
The present invention relates, in general, to hand braking
apparatus for railway cars and, more particularly, this invention
relates to a new and unique ergonomic hand wheel assembly for use
on a railway car having a conventional type hand brake system which
provides a mechanical advantage that will enable a significant
reduction in the effort or force that is required to turn the hand
wheel while at the same time there is maintained a comparable
resultant turning force at the hand wheel hub so that, for example,
the input turning force at the hand wheel rim may be reduced from
about 125 pounds to about 50 pounds.
BACKGROUND OF THE INVENTION
Usually, as is generally well known in the railway industry,
when railway cars are taken out of a train and parked at a siding
or yard, the hand brakes on at least some of these cars are applied
as a precaution against unwanted or unexpected movement of the
cars. A typical railway car hand brake normally consists of
apparatus for manually applying a brake shoe or shoes against one
or more wheels of the railway car by either turning a hand wheel or
pumping a ratchet handle connected by gears and/or linkage to the
brake shoe engaging mechanism. It is, of course, essential that
the apparatus include a mechanism for releasing the hand brake and
causing the brake shoe or shoes to be disengaged from contact with
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the wheels.
Normally, either a cast or stamped metal gear housing is
attached on an outside wall portion of the railway car adjacent one
end thereof. Such gear housing having a rotatable shaft or drum
therein to which is attached one end of an elongated brake chain.
The hand wheel or ratchet handle assembly is interconnected through
gears, as necessary, to cause rotation of the shaft or drum during
an application of such hand brake. The brake chain extends through
the bottom portion of the gear housing with the lower, opposite end
thereof attached to a suitable brake linkage, so that manually
turning of the hand wheel in a given predetermined direction
(normally clockwise), or pumping the ratchet handle, will cause the
uppermost end of the brake chain to be wound onto the shaft or
chain drum, thereby drawing the brake chain tight and applying the
brake shoe or shoes against a wheel or wheels through the brake
linkage.
Although turning the hand wheel in the opposite direction will
normally operate to release the hand brake in proportion to the
extent of such turning, many such brake housings are provided with
a quick release, non-spin mechanism which can be utilized to
instantly and completely release such a hand brake without causing
the hand wheel or ratchet handle to spin.
In the case of conventional freight cars, the gear housing is
most commonly attached to an outer end wall of the railroad car
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adjacent to an end ladder, so that to turn the hand wheel or
operate the ratchet handle to apply the hand brake, the brake
person must normally climb at least a portion of the end ladder to
reach the hand wheel or ratchet handle, and then turn the hand
wheel or pump the ratchet handle with one hand while hanging on to
the ladder with the other hand.
Even though some hand wheels or ratchet handles may be low
enough that they can readily be reached by a brake person without
climbing onto the ladder, it may still be advisable for safety
reasons for the brake person to operate the hand brake from the
ladder in the event the railway car is in motion or can be put into
motion, to thereby minimize the risk of being struck by such a car
in motion.
Specifications of the American Association of Railroads (AAR)
currently require that a hand brake system disposed on a railway
freight car have a minimum force requirement of at least 125 pounds
to suitably set the hand brake. Accordingly, the gear arrangement
within the various prior art gear housings are normally designed
such that a 125 pound force on the hand wheel rim is required in
order to set the hand brake.
For heavier freight cars where an increased force may be
advisable, the common practice has been to utilize conventional
gear housings and systems but to substitute a hand wheel of larger
diameter so that a greater moment is effected thereby permitting
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the same turning force at the hand wheel to effect a greater
resultant force at the hand wheel hub. A necessary force of at
least about 125 pounds on the hand wheel, however, can be rather
strenuous particularly if a brake person must apply the hand brake
with one hand while holding onto the railway car with the other
hand.
SUMMARY OF THE INVENTION
This invention is predicated on my conception and development
of a new and unique ergonomic hand wheel having a planetary gear
system built directly into the hand wheel itself which provides a
mechanical advantage in that it permits a reduced input force at
the rim of the hand wheel for effecting the same output force at
the hub of the hand wheel. In essence, the inventive hand wheel is
addressed to a new and unique ergonomic hand wheel which can be
attached to virtually any currently existing hand brake system
which, by virtue of the ergonomic mechanical advantage provided by
the internal planetary gear arrangement, will render it much easier
for a brake person to turn the hand wheel for purposes of applying
the hand brake to thereby render the hand wheel turning operation
not only easier but also significantly safer.
In summary, and in its broadest sense, the inventive ergonomic
hand wheel of this invention includes a manually operable, hand
wheel disk member adapted for manual rotation about an axis of
rotation, as in the case of any conventional hand wheel. The new
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and unique planetary gear arrangement has a sun gear rigidly
interconnected to the hand wheel disk member, with the axis of the
sun gear corresponding with the axis of rotation of the hand wheel
disk member. A hub member, also having a rotational axis aligned
with the axis of rotation of the hand wheel disk member, is
interconnected to the hand wheel disk member such that the hub
member is independently rotatable relative to the hand wheel disk
member about the same axis of rotation, with a means disposed on
its back side at the axis of rotation, for attaching the hub member
to a conventional rotatable drive shaft or drive member of the hand
brake system on the railway car. A plurality of planetary gears
are rotatably attached to the hub member which are positioned to
encircle the sun gear and adapted to mesh with and engage the sun
gear, while a stationary ring gear is disposed around the plurality
of planetary gears, meshing and engaging the planetary gears, such
that rotation of the hand wheel disk member, and accordingly
rotation of the sun gear through a given rotational arc, will cause
rotation of the planetary gears such that the planetary gears are,
in essence, caused to roll between the rotating sun gear and the
stationary ring gear, thereby imparting orbital motion to the
rotating planetary gears as well as the hub member to which the
planetary gears are attached. The orbital rotation of the
planetary gears and hub member will revolve through an orbital arc
less than the rotational arc traveled by the sun gear, to thereby
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provide a mechanical advantage.
In a more specific sense, a presently preferred embodiment of
the inventive ergonomic hand wheel of this invention includes three
basic components; namely a front housing assembly joined to a back
housing assembly with a stationary internal gear housing assembly
joined therebetween. The front housing assembly includes a
stationary front housing disk to which a sun gear mounting plate is
rotatably attached. A sun gear, as well as a hand wheel disk
member, are rigidly attached to the rotatable sun gear mounting
plate, such that the sun gear is rotatable upon manual rotation of
the hand wheel disk member. The back housing assembly includes a
stationary back housing disk to which the hub member is rotatably
attached. The rotatable hub member includes means disposed on the
back side at the axial center thereof for attaching the hub member
to a hand brake drive shaft of a hand brake system on a railway
car. Also included on the hub member is a plurality of gear axles
which are attached to the rotatable hub member in an aligned,
parallel and equally spaced relationship relative to the axial
center. A planetary gear is rotatably mounted onto each gear axle
such that the planetary gears will lie in the plane of the sun gear
and each will mesh with and engage the sun gear, such that rotation
of the sun gear will cause rotation of the planetary gears. The
stationary internal gear assembly includes a means for attaching
the assembly to an independent structural element for the purpose
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of maintaining the assembly stationary relative to the rotatable
components of the front and back housing assemblies, as well as a
stationary ring gear having a gear race on the inside surface
adapted to encircle, engage and mesh with the plurality of
planetary gears. Accordingly, any manual rotation of the hand
wheel disk member will cause a like rotation of the sun gear, and
accordingly, a reactive rotation of the planetary gears meshed with
the sun gear. However, since the planetary gears are also meshed
with the stationary ring gear, the rotating planetary gears will in
essence be caused to roll along the internal gear race of the ring
gear, thereby imparting an orbital rotation to the planetary gears
as well as the gear axles on which they are mounted about the
rotating sun gear. Since the gear axles are put into an orbital
rotation, that rotation is imparted to the rotational hub member of
the back housing assembly, through a rotational arc which is less
than the rotational arc of the sun gear and the hand wheel disk
member.
OBJECTS OF THE INVENTION
It is, therefore, one of the primary objects of the present
invention to provide an ergonomic hand wheel assembly for a hand
brake system disposed on a railway freight car which has a means
incorporated therein to provide a mechanical turning advantage to
significantly reduce the effort or force normally required to turn
the hand wheel and thereby apply the hand brake.
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Another object of the present invention is to provide an
ergonomic hand wheel assembly for a hand brake system disposed on
a railway car which is substantially easier for a brake person to
turn for purposes of applying the railway car's hand brake.
A further obj ect of the present invention is to provide an
ergonomic hand wheel for a hand brake system on a railway car which
not only requires less effort to turn but, also, can easily be
turned with one hand.
Still another object of the present invention is to provide an
ergonomic hand wheel for a hand brake system on a railway car which
requires less effort to turn and can readily be attached to any
existing hand brake system on a railway car without any significant
retrofitting effort.
An additional object of the present invention is to provide an
ergonomic hand wheel for a hand brake system on a railway car which
requires less effort to turn and, therefore, provides a number of
safety advantages as compared to a hand wheel of the prior art.
Yet still another object of the present invention is to
provide an ergonomic hand wheel for a hand brake system on a
railway car which can reduce the input turning force at the hand
wheel rim from a typical 125 pounds to about 50 pounds.
In addition to the various objects and advantages of the
invention described above, a number of additional objects and
advantages of the ergonomic hand wheel of the present invention
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will become more readily apparent to those persons skilled in the
railway braking art from the following more detailed description of
the invention, particularly, when such description is taken in
conjunction with the attached drawings and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure I is an isometric view of a hand wheel in accordance
with a presently preferred embodiment of this invention viewing the
back-side of the inventive hand wheel;
Figure 2 is a cross-sectional side view of the hand wheel
shown in Figure 1 with the section taken through the axial center
of the hand wheel; i.e., the axis of rotation;
Figure 3 is essentially the same as Figure 2 except that it is
enlarged to better illustrate the gear arrangement;
Figure 4 is an isometric view of the front housing assembly
showing the sun gear secured to a rotatable sun gear mounting
plate;
Figure 5 is a side view of the front housing assembly shown in
Figure 4;
Figure 6 is an isometric view of the back housing assembly
showing the planetary gears rotatably attached to a rotatable hub
member;
Figure 7 is a side view of the back housing assembly shown in
Figure 6;
Figure 8 is an isometric view of the internal gear housing
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showing the ring gear rigidly attached to a ring gear mounting
plate;
Figure 9 is a side view of the internal gear housing shown in
Figure 8;
Figure 10 is a plan view showing the arrangement of the
various gears when the hand wheel is properly joined together in a
completed condition; and
Figure 11 in an isometric view of another presently preferred
embodiment of the invention substantially like that shown in
Figure 1, except that a ratcheted lever arm is utilized in place of
a hand wheel.
DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION
Prior to proceeding with the more detailed description of the
present invention, it should be noted that for the sake of clarity,
identical components which have identical functions have been
identified with identical reference numerals throughout the several
views illustrated in the attached drawing figures.
Now reference is made, more particularly, to Figures I-3 which
illustrate a presently preferred embodiment of this invention. As
shown, the inventive ergonomic hand wheel, generally designated 10,
essentially comprises a hand manipulation member, such as a hand
wheel disk member 12 having a circular outer perimeter 14 adapted
for manual manipulation around an axis of rotation AX.
The embodiment illustrated shows such hand wheel disk member
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12 having a beveled peripheral flange 16. Adjacent to the beveled
peripheral flange 16 and spaced away from the axis of rotation AX,
the hand wheel disk member 12 can be of any desired form designed
for easy manipulation, including that of a ratcheted lever arm, as
will be described hereinafter.
The hand wheel disk member 12 is interconnected to a front
housing assembly 20. Specifically, the front housing assembly 20
(Figures 4 and 5) comprises a generally stationary front housing
disk 22, having a sun gear mounting plate 24 rotatably attached
thereto with the hand wheel disk member 12 directly or indirectly
attached to the sun gear mounting plate 24. A sun gear 26 is also
secured to such sun gear mounting plate 24, for example, with a
plurality of bolts 27, while a spacer member 28 is also attached to
such sun gear mounting plate 24 (Figures 2 and 3) at holes 30
(Figure 4). The hand wheel disk member 12 is accordingly attached
to the spacer member 28, such that rotation of hand wheel disk 12
will cause rotation of sun gear mounting plate 24 within such front
housing disk 22, and of course, a like rotation of sun gear 26.
Sun gear mounting plate 24 and sun gear 26 are each circular
in configuration, with each having an axial center that is aligned
with the axis of rotation AX of such hand wheel disk member 12, so
that manual rotation of hand wheel disk member 12 will cause sun
gear mounting plate 24 and sun gear 26 to rotate on their axial
centers, which correspond with the axis of rotation AX.
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Regardless of any variation in the interconnecting members,
the primary objective for the front housing assembly 20 is to
permit manual rotation of the hand wheel disk member 12 as
necessary to impart an identical rotation of the sun gear 26.
A back housing assembly 40, illustrated in Figures 6 and 7,
comprises a generally stationary back housing disk 42, having a hub
member 44 rotatably attached thereto. A means, such as socket 46,
extends from back side of hub member 44 which is essentially
provided for attaching the ergonomic hand wheel 10 onto a drive
member 8 of a hand brake system on a railway car (not shown). The
front side of such rotatable hub member 44 is provided with a
plurality of parallel gear axles 48, which perpendicularly extend
from hub member 44 and are substantially uniformly spaced around an
axial center thereof, and a planetary gear 50 is rotatably mounted
onto each gear axle 48.
The arrangement of the gear axles 48 and sizes of the
planetary gears 50 must be such that the planetary gears 50 will
lie in the plane of the sun gear 26, to thereby engage and mesh
with the sun gear 26, so that rotation of the sun gear 26 will
cause a uniform reaction rotation of the planetary gears 50,
rotating on gear axles 48.
An internal housing assembly 60, as illustrated in Figures 8
and 9, comprises a generally stationary internal housing disk 62,
having a ring gear 64 rigidly attached thereto. Ring gear 64 is
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provided with a gear race on the circular inside surface which is
adapted to encircle all of the planetary gears 50, and to engage
and mesh with the planetary gears 50, such that rotation of the
planetary gears 50 will necessarily cause them to roll along the
stationary gear race on ring gear 64.
In addition to the above, a means is provided on the internal
housing assembly 60, such as a flange 66, which serves the purpose
of providing a means for securing the internal housing assembly 60
to an external structural element to thereby prevent rotation of
internal housing disk 62 and ring gear 64 rigidly attached thereto,
regardless of any rotation of either the sun gear mounting plate 24
or the hub member 44.
The front housing assembly 20 is joined to the back housing
assembly 40, with the internal housing assembly 60 sandwiched
therebetween. As can be seen in the drawings, a plurality of
equally spaced holes 70 are provided through the faces of such
front housing disk 22, the back housing disk 42, and such internal
housing disk 62, which must be aligned and through which bolts (not
shown) are inserted for purpose of joining the three assemblies
together as above described.
While Figures 4-9 illustrate one each independent stationary
front housing disk 22, stationary back housing disk 42 and
stationary internal housing disk 62, these can be individual disks
as shown, and bolted together as noted above, or can in fact
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comprise just a single disk or a pair of disks provided that sun
gear 26 is rotatable with respect to any such disk or group of
disks, and that the hub member 44, with the planetary gear axles 48
is also rotatable with respect to any such disk or group of disks,
as well as being independently rotatable with respect to the sun
gear 26.
When properly joined together, as described above, it should
be apparent that with any manual rotation of such hand wheel disk
member 12 it will cause sun gear 26 to rotate equally therewith,
and that rotation of such sun gear 26 will cause the planetary
gears 50 to reactively rotate on gear axles 48. Since ring gear 64
is stationary, however, and meshes with the plurality of planetary
gears 50, it is apparent that as the planetary gears 50 rotate on
gear axles 48, they will be caused to roll along the inner gear
race of ring gear 64. This will cause the planetary gears 50 and
the gear axles 48 to orbitally rotate about the sun gear 26, with
an identical orbital rotation of such hub member 44, to which gear
axles 48 are attached.
It should be further apparent, that the rotation of planetary
gears 50 on gear axles 48 will, in essence, cause them to roll
between rotating sun gear 26 and stationary ring gear 64, such that
gear axles 48, in essence, will orbit midway between the rotating
sun gear 26 and the stationary ring gear 64. It should be apparent
that some orbital rotation will be imparted to the rotatable hub
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member 44, to which the gear axles 48 are attached.
It should be further apparent, however, that the extent of
angular rotation and the angular rate of the hub member 44 will be
somewhat less than the extent of angular rotation and angular rate
of sun gear 26, which is, of course, responsible for the mechanical
advantage created by the inventive ergonomic hand wheel. The
degree of such mechanical advantage will, of course, depend upon
the comparative radii of the sun gear 26 and the pitch diameter of
the planetary gears 50 should be substantially equal to the radius
of ring gear 64.
In an experimental model of this invention, utilizing a sun
gear having a radius of 1.33 inches, and planetary gears having a
radius of 0.83 inch, a mechanical advantage of 3.25:1 is achieved.
Because the ergonomic hand wheel assembly of this invention is
significantly easier for a brake person to turn, and the resultant
turning force at the hub will significantly exceed manual turning
force at the hand wheel disk rim, it is desirable to provide a
means for preventing an over application of the brake applying
force which could damage the system or apply the hand brake so
tightly that a conventional quick release mechanism will not
function.
One presently preferred means for preventing such an over
application of the hand brake within the embodiment illustrated
herein includes a more or less conventional torque limiting device,
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comprising a thermoset laminate and wave spring 80 disposed between
the ring gear 64 and any stationary element intended to retain the
ring gear 64 in a stationary position.
As shown in both Figures 2 and 3, such a torque limiting
device, comprising a thermoset laminate and wave spring 80 is
sandwiched between the forward face of ring gear 64 and front
housing disk 22. In this particular arrangement, front housing
disk 22 and back housing disk 42 are bolted together through
apertures 70 either with or without an internal housing disk 62.
In this particular embodiment, the stationary position of ring
gear 64 is maintained by the frictional compressive force at the
interface between ring gear 64 and front housing disk 22 and such
that ring gear 64 is otherwise rotatable relative to internal
housing disk 62 and back housing disk 42. In this particular
embodiment, the thermoset laminate and wave spring 80 are annular
in shape so that they can be positioned between the ring gear 64
and front housing disk 22, such that the frictional interface
contact is the only force keeping ring gear 64 in a stationary
position with front housing disk 22, back housing disk 42 and an
internal housing disk 62, if utilized.
The combined thermoset laminate and wave spring are
accordingly designed so that when a predetermined "break-away"
torque is achieved, the frictional force will be overcome, thereby
allowing ring gear 64 to orbit with planetary gears 50. By
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achieving such a break-away and permitting ring gear 64 to rotate
with planetary gears 50, it should be apparent to persons skilled
in the art that the ring gear 64, as well as planetary gears 50,
will be caused to rotate in situ, so that no orbital rotation is
imparted to the gear axles 48 or hub member 44.
As noted above and as an alternative embodiment, for example,
the hand wheel 12 could be fabricated in practically any desired
form. In this regard, it should be further apparent that a lever
arm 12a, with or without a conventional ratchet mechanism 13, could
be substituted for the hand wheel disk member 12, as illustrated in
Figure 11. In this embodiment, no particular modifications would
have to be made other that adapting the lever arm 12a to
effectively rotate the sun gear 26 substantially as described
above. In addition, and as noted in the specification, the means
for housing the various gear elements and rotatable elements could
take a variety of different forms, with or without one or more
stationary disk member as illustrated.
In view of the above detailed description of the inventive
ergonomic hand wheel of this invention, it should be apparent that
numerous modifications could be made and differing embodiments
utilized, without departing from either the spirit of the invention
or the scope of the appended claims.
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